1. Field of the Invention
This invention relates to package of wound elastomeric fiber and a method for the same. In particular, the invention relates to precision wound spandex.
2. Description of Related Art
In winding a yarn or multi-filament fiber onto a package, the package is typically rotated and the yarn is fed to the circumferential surface of the package and distributed axially along the package by a traverse arrangement, such as a reciprocating fiber guide. In random winding, the package is rotated, typically, by frictional contact with a drive roller acting directly on the surface of the package, or by directly powering the chuck holding the packages which are in contact with a non-driven roller. The package has typically the same surface speed as the roller and is typically kept constant during winding. As the surface speed is constant, a declining rotational speed of the package occurs as the package increases in diameter, while the traversing apparatus reciprocates the fiber at a nominally constant frequency. As a result, the yarn lay is random, giving the term of “random winding” to this technique. One problem of random winding is that as the package grows to certain diameters successive turns of yarn (or every other or every third or fourth turn of yarn) may lie one on top of one and the other, giving rise to ribbons of yarns which tend to not only distort the package shape, but may also adversely affect subsequent unwinding of the yarn from the package. These ribbons also cause undesirable vibrations in winding and unwinding which can result in fiber disturbances, such as tangles and breaks.
Surface winding of an elastomeric yarn, such as spandex, is a difficult process because of the very low tension developed in the fiber due to its highly elastomeric properties and to its very sticky nature. To develop enough tension to process the fiber in spinning, a significant amount of stretch is required. Due to the high stretch required, the wound yarn cake will be under high internal tension which may cause the core fibers of the wound cake to begin to fuse together. Furthermore, ribbons that may be formed during random winding represent regions of higher density, compared to other portions of the cake. With random winding of elastomeric yarns, such ribbons may lead toward the fusing of yarns within the yarn package.
Thus, there is a need in the art to improve winding techniques, especially for elastomeric yarns, to avoid problems associated with the prior art.